While 19 officers waited in the hallways of Robb Elementary School because the incident commander believed the situation had transitioned to a barricaded subject, the Uvalde Consolidated Independent School District was sending out alerts to parents warning them of an active shooter in the building. 

"Uvalde CISD parents, there is an active shooter at Robb Elementary. Law enforcement is on site," a school official said at 12:20 p.m. in a 45-second message, audio of which was obtained by KSAT. "Your cooperation is needed at this time by not visiting the campus."

The message was sent 47 minutes after 18-year-old Salvador Ramos entered the school and killed 19 children and two teachers. 

Robb Elementary is Uvalde is pictured following the mass shooting

Crime scene tape surrounds Robb Elementary School in Uvalde, Texas, on Wednesday, May 25. (AP/Jae C. Hong)

Another half an hour lapsed before a Border Patrol team breached the classroom door and killed Ramos shortly before 1:00 p.m.

PRESIDENT BIDEN CONSIDERING RAZING, REBUILDING ROBB ELEMENTARY SCHOOL

Texas Department of Public Safety Director Steven McCraw said Friday that the incident commander, Uvalde school police chief Pete Arredondo, believed that the situation "had transitioned from an active shooter to a barricaded subject."

"Obviously, based upon the information we have, there were children in that classroom that were at risk and it was in fact still an active shooter situation and not a barricaded subject," McCraw said. 

"There [were] 19 officers in there. In fact, there [were] plenty of officers to do whatever needed to be done, with one exception, is that the incident commander inside believed they needed more equipment and more officers to do a tactical breach at that point."

Children run to safety during a mass shooting

Children run to safety after escaping from a window during a mass shooting at Robb Elementary School where a gunman killed nineteen children and two adults in Uvalde, Texas, U.S. May 24, 2022.  (Pete Luna/Uvalde Leader-News/Handout via REUTERS)

Arredondo has not responded to the Texas DPS's request for a follow-up interview in the last two days, officials said Tuesday. 

CLICK HERE TO GET THE FOX NEWS APP 

The Justice Department has launched a federal review of the law enforcement response to the shooting. 

"The goal of the review is to provide an independent account of law enforcement actions and responses that day, and to identify lessons learned and best practices to help first responders prepare for and respond to active shooter events," the DOJ said on Sunday.